Genetic information, variation and relationships between organisms Flashcards
Describe the process of transcription in protein synthesis
- By action of DNA helicase hydrogen bonds between bases are broken
- One strand of the DNA acts as a template strand as contains the desired gene in DNA strand
- Free RNA nucleotides align by complementary base parings
- In RNA Uracil base pairs with adenine on DNA
- RNA polymerase joins nucleotides forming phosphodiester bonds
- Pre - mRNA is then spliced removing introns forming mRNA
What happens during splicing of pre mRNA ?
Introns are removed
Describe the process of translation in protein synthesis
- mRNA attaches to a ribosome
- Ribosome moves to / finds the start codon
- tRNA anticodons bind to complementary mRNA codons
- tRNA brings a specific amino acid
- Amino acids join by peptide bonds
- Amino acids join together with the use of ATP
- tRNA released after amino acid joined to polypeptide
- The ribosome moves along the mRNA to next two codons to form the polypeptide chain
Give the 4 differences between mRNA and tRNA
mRNA - linear, tRNA - clover leaf shape
mRNA - no amino acid binding site, tRNA - amino acid binding site
mRNA - longer, more nucleotides, tRNA - shorter, less nucleotides
mRNA - codon, tRNA - anticodon
Give 4 differences between DNA and RNA
DNA - double stranded, RNA - single stranded
DNA - thymine, RNA - uracil
DNA - deoxyribose, RNA - ribose
DNA - long, RNA - short
Describe how ATP is resynthesises in cells
From ADP and Pi
By ATP synthase
During respiration/photosynthesis
Give two ways in which hydrolysis of ATP is used in cells
Provide energy
To add phosphate to other substances and make them more reactive
In a eukaryotic cell, transcription results in a molecule of pre mRNA that is modified to produce mRNA. In a prokaryotic cell transcription produces mRNA directly. Explain the difference
DNA of eukaryotic cell has non coding regions (introns)
These are removed after transcription
